Since one of my three mice (Tremolo) died a month ago, I have observed some curious behaviours in the remaining two (Pizzacato and Collengno).

First of all, the two remaining mice seem to be fighting more often than before. Both were pretty active prior to the death of Tremolo, but now only Collegno seems to be as active as she was; Pizzacato spends a lot more time in her bed. Secondly, All three mice used to be very excited to see us/used to beg to come out/be picked up, but now neither of them seem particularly interested in coming out, and Pizzacato doesn't walk straight onto our hands anymore (she used to compete with Tremolo to see who could get to us fastest). I don't know if she could still be sad about the loss of her sister? Or maybe she's just bored? I don't know. I try to keep their tank interesting by changing up the layout and building/putting in different toys weekly, and we try to get them out every day (although sometimes they really don't seem to want to). Could she be wanting the company of more than one mouse (who seems to occasionally bully her!)?

Something else that happened at the same time as Tremolo dying, was that Collegno had a really bloated belly (I posted about this at the time). Advice from the forum was to cut out fresh foods for a week or so, which we did, and the problem resolved itself. Then the problem recurred a couple of weeks later, so we cut out fresh foods again. Again, the bloating went away, but now she's got really runny bowel movements. She is completely fine and normal in herself otherwise, and we spoke to a vet who just told us to monitor her for another week (this has already been going on for a week). Their food hasn't changed, her appetite is the same, she's drinking the same...I just don't get it. Nothing has changed. Pizzacato is not experiencing anything similar, so I'm really stumped! Could she have developed an allergy to something in her food?

Just like people, sometimes mice get upset tummies and diarrhea. It usually clears up on it's own but you can add plain dry oatmeal to their diet, it will help firm things up.

About the behavior of your two mice... Mice do best is groups of three. Groups of two tend to bicker a lot. In order for the group dynamics to be right for mice, they need to in groups of three. One mouse emerges as the alpha, one as a beta, and one as a peacekeeper. Some mice do okay in pairs but it sounds like your girls might need another friend.

That's really interesting; I've been giving them oats as a treat when they come out of their tank, and I happened to handle them shortly after writing my last post and noticed Collegno's droppings had firmed up a bit! I will perhaps include more oats in their main mix. Thank you!

I did not know groups of two mice tend to bicker a lot. I suspect you are right and that they need another friend or two. We were hoping to get a couple more mice next weekend, but the breeder can no longer meet with us then. I'll have to sort something else out!

I'm realising that being a pet owner is much like being a parent; you worry about them all the time and constantly discuss poo!

So, Collegno's stools have mostly become firmer since introducing a higher ratio of oats into her diet. We ran out of the muesli we were using, and I couldn't get any more of the same brand, so annoyingly I've had to introduce a different brand at this critical time! Since doing so, they've become slightly looser, slightly redder/orange-ier, and occasionally she will leave what I can only describe as a "jelly-like" deposit behind! Again, she still seems absolutely fine in herself. Pizzacato is absolutely fine in herself. I don' think the red/orange tint is blood, as looking at the new food mix it has some really orange pellet-things in it (link), and Pizzacato's looked slightly orange, too. Still, the jelly-type poos are weird, right? Anyone seen this sort of thing before?

Also, she seems to poo pretty constantly. It was only after picking up my new mice at the weekend (safely quarantined, different floor of the house, practising good hygiene between cage contact! Pictures soon. ) that it ocurred to me she really does seem to be going a lot. Can this be normal for mice, too? Just a different physiology to other mice?

I have seen jelly-like excrement occur in instances of highly irritated human bowels, often where gluten sensitivity is a factor. It was mucus. Strict avoidance of wheat/rye/barley eliminated the symptom and the pain in the gluten sensitivity instances.

I don't know how that directly applies to a mouse -- since grain is so important to their diet, a gluten-intolerant mouse would indeed be at a disadvantage. However, something else may be causing irritation. It might be that there is quite a belly ache going on in that little mouse from one thing or another (food, illness, intestinal bugs, stress). Looking at this from the point of view of the afflicted mouse, I think I'd rather that it go away as soon as possible, but animals are more stoic than we humans, and just seem to accept pain as a "new normal" and try to keep going.

Maybe you could call her vet just to ask about it, and they can tell you over the phone whether an office visit is necessary, or if you just need to make an adjustment to something.

Best of luck.

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